[v3-1-test] fix(api): disable uvloop if PYTHONASYNCIODEBUG=1 to prevent segfault (#61281)

[jason810496]

• fix(api): disable uvloop if PYTHONASYNCIODEBUG=1 to prevent segfault (issue API server segfault when PYTHONASYNCIODEBUG=1 #61214)

• docs(newsfragment): add newsfragment for uvloop/asyncio debug segfault fix (API server segfault when PYTHONASYNCIODEBUG=1 #61214)

• fix(api): add stacklevel for debug warning and fix rst literals

• fix: remove else block and correct newsfragment per review feedback

• docs: document PYTHONASYNCIODEBUG/PYTHONDEVMODE incompatibility (Python 3.12+)

• docs: fix RST formatting and spellcheck errors

• Add blank line after warning directive to fix RST error
• Quote asyncio with backticks to fix spellcheck

• refactor: simplify to warning-only approach per reviewer feedback

• refactor: apply reviewer suggestions

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(cherry picked from commit 004f790)

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